Monitor 12 Series 2 crossover re-cap advice/help

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Hey, all!

I'm going through my old posts, reading through other's posts, and trying my best to understand what I have and what I need to order.

But I still feel like I'm the town idiot =(

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Here's a picture of my crossover:

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- I've got one more cap than the fantastic list from the exhaustive crossover thread in the forums. Here's the list:

Monitor 12
4.2uF capacitor
12uF capacitor
12uF capacitor
16.4uF capacitor
2 ohm resistor

- So what the heck is this thing:

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- I'm leaning towards Solen or Dayton to get the 12s up and running. I notice Solen sells Dayton on their site. What gives? I thought Dayton was made by Bennic? Would any of you recommend a different capacitor for me to buy in this price range? (Maybe in the future I can afford Sonicaps or similar, but for now...).

- If I can't get a 16.4 cap, I can get a 15 and a 1.5 and wire them together, right?

- Side questions:

1) Would any of you replace the wiring from the crossover to the speakers? And, if so, with what?

2) What is your preferred cleaner for the cones/surrounds on these old Polks? They could use some tidying up...

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So this is where I am on the crossovers. I'm ready to get what I need, but (as you can see) I'm a complete n00b when it comes to this.

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And then... the next project will mean I'll be asking for help when I put my SL2500s from the 12s in my 5s and re-do those crossovers to match... Whee!

agfrost

Looks like a fun project!

I'm guessing the piggy-backed dark blue/light blue stack are capacitors paralleled to add to the 16.4uF of C1 on the schematic. I can't see the values on the other capacitors to confirm, but this seems likely. It seems you are aware that capacitors in parallel add (based on your question about 15uF and 1.5uF).

On that thought, you'd be best off splitting the capacitance evenly to make your 16.4 uF--This works well because 8.2uF seems to be an easy value to find.
I'm not a huge fan of Solen, largely based on what I've heard about them/their sound. In the budget range the Daytons can work, here are the 8.2uF Daytons at Parts Express; They've got the other values you'd need too.

You may wish to look into Clarity PX, their budget cap--PartsExpress carries them: Clarity PX 8.2uF

Finally, if you can fit it in your budget to splurge just a little bit, you could get a better cap for position C3 (you can see that Polk did so, putting in a Mylar cap, the yellow one, on the original board rather than the electrolytics they installed elsewhere. Keeping it in the Clarity family, Clarity CSA is nice.

Hopefully some others will chime in with their thoughts and experiences. Have fun with your project and keep asking Q's if/as you have them!

Jay

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agfrost wrote: »

Looks like a fun project!

Finally, if you can fit it in your budget to splurge just a little bit, you could get a better cap for position C3 (you can see that Polk did so, putting in a Mylar cap, the yellow one, on the original board rather than the electrolytics they installed elsewhere. Keeping it in the Clarity family, Clarity CSA is nice.

Hopefully some others will chime in with their thoughts and experiences. Have fun with your project and keep asking Q's if/as you have them!

Jay

- Thanks, Jay!

- I'll look at the Clarity caps!

- Tomorrow is strip-my-Rti10's-down-and-put-the-parts-on-ebay day. I can't argue with the extra money I'd get out of them by parting them out, but wasting a beautiful pair of cabinets does hurt... Maybe I'll use them for something bizarre...

- I was testing tweeters a couple of days ago, and checking to see just how bad the 12 with the not-dead-yet crossover sounds. UGH. Awful. No sparkle at all. The re-foamed Boston T830's sound a lot better, even if they don't have a lot of oomph.

But I put the 2500's in the Polk 5's, and pulled the 2000's to sell for a few bucks (to add to the Great Tweeter and Cap Purchase).

Slightly unrelated tangent:

- I saw a post somewhere once where a guy pulled the white polyfill slabs stuffed in his 12's and replaced it with eggcrate foam attached to the interior surfaces. I have never understood how stuffing cabinets works consistently when the method of stuffing is so haphazard.

#1: Each of my cabinets is stuffed a slightly different way, and stuffing has settled differently, and the space between drivers and stuffing is different, and... it seems that would affect the sound.

#2: I never understood how a driver's specs can say 'put me in a cabinet of X interior volume...' so you do... but then you fill the void with polyfill. I thought the stuffing was to dampen interior reflections, but it also tricks the driver into reacting like the enclosure is bigger on the inside than it is? Right? Some people only coat/cover the interior surfaces, and some people stuff the cabinet. Are those things working at cross purposes? I mean, if you're adding coverings to interior surfaces, shouldn't the volume of the cab for the drive be calculated based on the dimensions from interior covering to interior covering?

I was thinking of taking the drivers out and coating the interior with some deadening material (the cabinets aren't as dead, when you knock on them, as my other speakers). And I wasn't sure I wanted to stuff them in the same was if I can improve on it.

And thus ends my musings for today...

-Steve(n)

F1nut

You can easily over damp a speaker cabinet by coating the walls. Best to stick with the poly fill.

westmassguy

Do not forget to replace the Polyswitch. In this design, you cannot eliminate it like we do with other crossovers from that era. RUE090 is the current part number.

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F1nut wrote: »

You can easily over damp a speaker cabinet by coating the walls. Best to stick with the poly fill.

Hey F1!

(edited for my ignorance, doh!)

- Stick with poly? Will do. I wish there was a good primer on damping out there.

Just took the pieces off the board tonight.

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westmassguy wrote: »

Do not forget to replace the Polyswitch. In this design, you cannot eliminate it like we do with other crossovers from that era. RUE090 is the current part number.

I'll make sure I do this

Your Franken/not-Frankenpolk projects are awesome, btw.

F1nut

plastic_avatar wrote: »

F1nut wrote: »

You can easily over damp a speaker cabinet by coating the walls. Best to stick with the poly fill.

Hey F1!

(edited for my ignorance, doh!)

- Stick with poly? Will do. I wish there was a good primer on damping out there.

Just took the pieces off the board tonight.

Don't do a halfass job, remove those old leads and solder the new components to the board properly.

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F1nut wrote: »

Don't do a halfass job, remove those old leads and solder the new components to the board properly.

Will do.

Probably would've taken another 3 minutes to just unsolder rather than snip and then go back to it... Rookie mistake. I'll forget the snips and just desolder the other crossover from the start.

agfrost

If you haven't gotten that far yet, it's not a bad idea to leave one crossover original while constructing a new one, as a model for 'which parts go where'.

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agfrost wrote: »

If you haven't gotten that far yet...

Just looking at the first one tonight to finish with getting those wires out.

So, will do

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westmassguy wrote: »

Do not forget to replace the Polyswitch. In this design, you cannot eliminate it like we do with other crossovers from that era. RUE090 is the current part number.

Hey. Question:

Is there an equivalent I can use that will work?

I'm asking because I'm going to have to go with Dayton's on my rebuild and I'm looking at the limited offerings on Parts Express.

(Since I'm Pandemic Time affected, saving some dollars and doing the best I can is the option I need to choose to get these up and running... so I hoped I could order everything on the site... but those polyswitches, damn it...)

https://www.parts-express.com/cat/speaker-protection-devices/307

Having a hard time finding somewhere to buy a couple of the things...

(edit)

I just found these... but they do look different:

https://www.westfloridacomponents.com/F118APP09/40A+30V++PTC+PolySwitch+Resettable+Fuse+Raychem+RUE090-1.html

F1nut

The RUEF090 is the correct substitute for the RUE090.

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F1nut wrote: »

The RUEF090 is the correct substitute for the RUE090.

Woot!

Ordered!

Thank you!

I know it's a little disappointing that I had to adjust my brand goals for the rebuild, but I am excited to do my first crossover fix on speakers I loved even as they were going bad

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All other crossover bits ordered and being delivered soon.

I know I went low end, but I did the best I could with Dayton right now.

In the future, it'll be neat to see differences if I'm able to upgrade to other brands.

I was going to get that Clarity cap for the big 12, but it was out everywhere I looked last month =(

Crazy thing I found out:

Rebuilding the crossover and upgrading the tweeter on my 5B is almost the same cost as the 12!

Well, to me that's crazy... The 30 cap is the killer. I spec'd it Dayton, since I was in there on Parts Express anyway... and it looked like I'd have to use two 15 since a 30 wasn't listed.

Anyhow, I'd love to rebuild the 5B to go with my Realistic STA-960 and recently thrifted Lab-420, but not for a while I suppose...

I hope the parts are here this weekend for the 12! I'm super excited to get working on them!

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I'll post pictures later and as I go, but here's the report!

- Upgraded crossovers! Woot!

However... the resistor I got is HUGE. The way I placed it on crossover 1 works, but it's ugly. I realized there was a better way, so I changed its position on crossover 2.

- Turns out one of my original tweeters is busted, but that's o.k... I ordered the 198's, and the Club Polk mention meant I got both *and* a pair of replacement outrigger feet for my Rti10 for $102 shipped via FedEx. Crazy!

Polk really does take care of its fans.

- The bass is a little boomy, so I'm going to experiment a little bit... nothing major.

I saw someone who coated the lower half of the cabinet to deaden it a little. I heard of people adding more bracing (but that takes away from the interior volume, and I don't want to do that... so I got some cheap Dynamat knock-off to see how that sounds. It could be the room, too. It is sub-optimal... and I do have an eq I can bring into the mix to compensate.

- The passive radiator is so light! I had no idea.

I'm rotating all the drivers/radiators, since they've been in one position for 30 years...

- I hooked the crossovers up to the speakers reversed... that was funny...

- Next year, if Rona hasn't made me a pauper, I think I'll re-do the laminate covering on the cabinets. Ah, daydreams...

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Is there a burn-in time for caps? Or is that just an old wives tale?

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The 2nd crossover's resistor placement was much better

Faustin

Yes, the second one looks better. You can always drill new holes in the pcb to re-position the components so they fit tight together, Just make sure you are drilling through the same trace. The caps should be tight to the board (use two sided heavy duty tape) and or hot glue and zip ties. . That first c/o looks pretty bad. Everything looks like they are floating in the air. Think about vibration. Don't want to be a jerk, but just saying.

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Faustin wrote: »

Don't want to be a jerk, but just saying.

Not at all!

My first time doing this. Mistakes were made [laughs].

I used hot glue to brace everything before I put them in the cabinets.

I never considered new holes! Newbie ignorance.

I don't know, yet, if they 'sound' better overall than the Boston T830's I have next to them, but the Polks are blowing my mind with the imaging and soundstage. It's the stereo effect I've been searching for. The Bostons have good tone, but not as much presence, and absolutely no imaging compared to the Polks.

pitdogg2

The stage is set the band starts playing and suddenly your heart starts pounding.....

F1nut

Ivan is in love....

pitdogg2

😲🤫

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Hey guys

So, weeks listening to the re-capped, re-sealed, and re-tweeted speakers and I have a question:

Have any of you ever had a hole in your midrange with these? Or any Monitor series of similar design (from 5 to 10, I'm guessing...)?

I noticed when I hooked up the eq and did some pink noise adjustments to see what would happen, that there was a dip in their ability to push out (I think) 500hz (I'd have to hook all that up again to be sure). Contrasted with the Bostons during the same time I was playing, there was no dip where I couldn't boost the frequency to flat.

If I play the Bostons and the Polks back and forth, there is something that's noticeably subdued (and possibly missing) on the Polk side somewhere in the midrange (on both speakers). I wondered if it could be a choice I made in the parts I used in the crossovers, or if it's just a design issue with this model or these drivers.

My G/god(s), do I love the tweeters, though

Even given this strange mystery of missing frequencies/amplitude?, the imaging is just so damn amazing. I've listened to more music in a sitting each time I sit down than I have in 10 years.

I wish I could explain the issue more at the moment, but I don't know what to do to test on a budget to get you guys more info for better help =\

F1nut

Start with checking that you have all the components where they are supposed to be.

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- Wires are correct on components.

- Wiring is correct in the 12's.

- Speaker wire = thumbs up

- I sent tones through the speakers via Bluetooth/Echo Dot/iPhone from a tone generator with the speakers hooked up to the HTR-5960.

- I didn't do a complete sweep, but I hit all the full and half stops (50, 100, 150, 200, 250, etc.., up to 15khz (I stopped there because it's just painful...)). All frequencies were audible and clear on the Polks.

- If I switch between the Bostons and the Polks using the same source/music, the Bostons are more fatiguing in the upper midrange to lower highs... but there is a presence in the... metallic and non-human sounds in what could be, for me, the upper middle mids to lower upper mids... so I guess I'll play with the tone generator a little more and see if there are any audible dips in those in-between frequencies I skipped.

- The Bostons do have louder/boomier bass, too... but it doesn't scale to be as listenable at higher volumes as the Polks. I know the Polks were boomier before I put the sound-deadening layer on the walls around the radiator.

I'll experiment a little more this week.

Gardenstater

You are using your ears as a measuring instrument which is fine. Why not also try playing some pink noise through your system and use a spectrum analyzer app on your phone to see what the freq. response curve looks like. See if you see your perceived dip around 500 Hz. Even if you see it, it could be some effect of your room acoustics.

ptrooper

Sound deadening on the walls around the radiator? I believe this will negatively affect the base interfering with the liquid coupling!

F1nut

ptrooper wrote: »

Sound deadening on the walls around the radiator? I believe this will negatively affect the base interfering with the liquid coupling!

100% correct.

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The Dynamat knock-off I used...

I have to say, I'm enjoying the sound quality of the low tones. And I know that's a subjective, ear comparison to them before the crossover rebuild and the sound deadening...

I had Wish you were here on lp playing last night, and the low notes... the vibrations, and the details, they were great. At one point I came up with a start because I thought there might be something wrong- the low tones were so strong on one part, it was startling. I checked the record player, and played it again. It was what I was supposed to be hearing, but I'd never played the lp on these speakers. It played great on the Bostons and my homebrews, but Welcome to the machine was AMAZING.

I'll try pink noise again, but I'll run it optical from my laptop and see what the phone says (or I could use my USB mic... it's a Yeti, not an audio testing mic...).

I sat my wife down and played some tunes from Red Hot + Blue for her (it's an AIDS awareness/tribute album).

I said 'Hey, where are the voices on the track?'

She looked up and pointed to the middle of the room under the tv.

I said 'O.k., where are the instruments?'

She looked from side to side and pointed at different places from the position of the Bostons (flanking the tv) and in-between.

I said 'Awesome. Those are unplugged. All that is coming from the Polks (which are flanking the Bostons).'

She asked me if I was mistaken.

I showed her the cables, unconnected.

It was the first time she'd ever experienced the glory of stereo

That's 2 family members who were surprised by the experience.

And my 15 year old daughter asked me today if we could listen to an album she wants me to hear tomorrow. [smiles YUGELY]

I appreciate everyone's help, and I'll do some more detective work on them this week.

Thank you all. I wouldn't have gotten this far without the input from everyone who's chimed in!

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ptrooper wrote: »

Sound deadening on the walls around the radiator? I believe this will negatively affect the base interfering with the liquid coupling!

[thinking about that...]

Here's some questions:

Because it's a super-thin, dense deadening material on the walls/floor of the passive's space, it should be protecting the air of the chamber from color, right?

By reducing unwanted cabinet vibrations and internal reflections, the sound coming from the passive should be purer than when it's left to bounce around and reverberate, right?

Wouldn't that explain the lack of boominess (and thus my initial perceived lack of bass until listening to multiple tracks over multiple genres)... since tracks with lower frequencies do present appropriate sounding tone?

All anecdotal, of course, without the use of measurement software and wizardry beyond what I have...

[trying to learn!]